ORGANIC-CRYSTALS IN THE TRACHEIDS OF TORREYA-YUNNANENSIS

Organic crystals were found in tracheid lumina of some samples of Torr eya yunnanensis Chen & L.K. Fu imported from Yunnan, China. Tracheids with crystals were found in short to long tangential bands along the g rowth ring boundaries. Because the crystals were rapidly dissolved wit h ethanol and xylene, cross and tangential sections were mounted in de -ionized water without staining and observed by biological, polarised light, and phase-contrast microscopy. The crystals were sublimated und er vacuum during routine sample preparation for conventional SEM and o nly the peripheral parts remained. With the aid of low vacuum-SEM and modified cryo-SEM procedure, the shape of the crystals was revealed. S ome were styloid and large enough to fill tracheid lumina, while other s were stacked appearing as slates filling tracheid lumina. X-ray diff raction applied to sections and isolated crystals showed that they wer e single crystals and orientated along the cell wall. UV spectra on is olated crystals and methanol dissolution of crystals suggested that th ey were composed of phenolic compounds. Crystals that were recrystalli zed from methanol were analysed by H-1 and C-13 nuclear magnetic reson ance spectroscopy. These two techniques revealed that the major and mi nor components were o-methoxy cinnamic acid and o-methoxy cinnamic ald ehyde.